Camera Ball Turret Having High Bandwidth Data Transmission to External Image Processor

ABSTRACT

An unmanned aerial vehicle (UAV) includes a fuselage, a gimbal-mounted turret having one or more degrees of freedom relative to the fuselage, a camera disposed in the gimbal-mounted turret for motion therewith in the one or more degrees of freedom, and a central video image processor disposed exteriorly of the gimbal-mounted turret, the central video image processor configured to receive and process image data from the camera.

TECHNICAL FIELD

The present disclosure relates generally to camera-equipped aircraft,for example unmanned aerial vehicles used for surveillance.

BACKGROUND

Aerial surveillance is an invaluable information-gathering tool. Inbattle settings, it provides intelligence about troop size, location,and movement, damage assessment, and a host of factors that are criticalto successful battle planning and prosecution. Various aircraft-mountedcameras can be used to provide the information in real time, in the formof still or moving (video) images, over a range of spectra includinginfrared for penetrating through visibility barriers such as haze andfor night time operation. The cameras can be fixed or movable,individually or collectively, relative to the aircraft. Gimbaledmechanisms effect camera movement, and generally comprise a turrettypically having two degrees of freedom relative to the aircraft. Motionof the turret-mounted camera can be automated, for example in a presetscanning pattern, or user-actuated depending on the specificapplication. For example, the operator can move or zoom the cameraconcentrate attention on a particular area of interest, to capturehigher resolution images, or to scan over a broad region in order todetect activity that warrants greater scrutiny, either in real time orduring subsequent analysis of the images. Information gathered throughsurveillance can be processed locally, onboard the aircraft, ortransmitted to remote operation centers.

FIG. 1 is a bottom view of an aircraft 100 on which a gimbaled turret102 is mounted. Disposed in the turret is a camera 104 whose mountingprovides it with the two degrees of movement indicated by the pair ofdouble-headed arrows in the drawing.

In addition to conventional manned aircraft, unmanned aerial vehicles,or UAVs, have gained widespread acceptance in the war theater. A primaryadvantage of UAVs is their pilotless nature, which reduces exposure andrisk to human life during operation. The absence of a pilot and otherhuman operators, with their attendant support systems, means the UAV canbe made smaller, and payload can be dedicated to other components, suchas armament and surveillance equipment. However, as reduced size becomesparamount, more exacting constraints are imposed. Among these are weightand range considerations, which translate to requirements of improvedaerodynamics and compactness. For these reasons, UAV-mounted camerasneed to be smaller and lighter in order to conserve power and range.Further, because of their exterior mounting, their design needs topresent less drag or wind resistance to the aircraft.

FIG. 2 is a schematic view of a conventional turret-mounted camera usedin a UAV. Some details of the camera include main optical components(lenses, etc.) 202, a sensor 204, and video processing circuit 206. Allof these components are mounted within ball turret 102. Processed imageinformation from the camera is delivered from the ball turret 102 to atransmitter (not shown) disposed in the fuselage of the aircraft. Themeans of transmission between the camera and transmitter can includecables 208 or other expedients, such as slip rings (not shown), that aredesigned to eliminate interference with the motion of the ball turretwhile contending with the large throughput of information necessary tosupport high resolution still or moving images. Transmission from thefuselage to the ground station is wireless, for example via RF.

SUMMARY

As described herein, an unmanned aerial vehicle (UAV) includes afuselage, a gimbal-mounted turret having one or more degrees of freedomrelative to the fuselage, a camera disposed in the gimbal-mounted turretfor motion therewith in the one or more degrees of freedom, and acentral video image processor disposed exteriorly of the gimbal-mountedturret, the central video image processor configured to receive andprocess image data from the camera.

Also as described herein, a surveillance method includes capturing imageinformation using a gimbaled camera mounted in a turret exterior to anaircraft fuselage, transmitting the captured image information to acentral image processor disposed in the aircraft fuselage, andprocessing the transmitted captured image information in the centralimage processor.

Also as described herein, a device includes means for capturing imageinformation using a gimbaled camera mounted in a turret exterior to anaircraft fuselage, means for transmitting the captured image informationto a central image processor disposed in the aircraft fuselage, andmeans for processing the transmitted captured image information in thecentral image processor.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and constitute apart of this specification, illustrate one or more examples ofembodiments and, together with the description of example embodiments,serve to explain the principles and implementations of the embodiments.

In the drawings:

FIG. 1 is a bottom view of a conventional manned aircraft having agimbaled ball turret in which a camera is mounted;

FIG. 2 is a schematic view of a conventional gimbaled turret-mountedcamera with some details thereof;

FIG. 3 is a block diagram of the system architecture for a UAV inaccordance with one embodiment described herein;

FIG. 4 is a block diagram showing a centralized image capture approach;and

FIG. 5 is a flow diagram of a surveillance process; and

FIG. 6 is a schematic diagram showing the surveillance operation of amulti-camera UAV in communication with a remote base station.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Example embodiments are described herein in the context of a camera ballturret having high bandwidth data transmission to external imageprocessor. Those of ordinary skill in the art will realize that thefollowing description is illustrative only and is not intended to be inany way limiting. Other embodiments will readily suggest themselves tosuch skilled persons having the benefit of this disclosure. Referencewill now be made in detail to implementations of the example embodimentsas illustrated in the accompanying drawings. The same referenceindicators will be used to the extent possible throughout the drawingsand the following description to refer to the same or like items.

In the interest of clarity, not all of the routine features of theimplementations described herein are shown and described. It will, ofcourse, be appreciated that in the development of any such actualimplementation, numerous implementation-specific decisions must be madein order to achieve the developer's specific goals, such as compliancewith application- and business-related constraints, and that thesespecific goals will vary from one implementation to another and from onedeveloper to another. Moreover, it will be appreciated that such adevelopment effort might be complex and time-consuming, but wouldnevertheless be a routine undertaking of engineering for those ofordinary skill in the art having the benefit of this disclosure.

In accordance with this disclosure, the components, process steps,and/or data structures described herein may be implemented using varioustypes of operating systems, computing platforms, computer programs,and/or general purpose machines. In addition, those of ordinary skill inthe art will recognize that devices of a less general purpose nature,such as hardwired devices, field programmable gate arrays (FPGAs),application specific integrated circuits (ASICs), or the like, may alsobe used without departing from the scope and spirit of the inventiveconcepts disclosed herein. Where a method comprising a series of processsteps is implemented by a computer or a machine and those process stepscan be stored as a series of instructions readable by the machine, theymay be stored on a tangible medium such as a computer memory device(e.g., ROM (Read Only Memory), PROM (Programmable Read Only Memory),EEPROM (Electrically Erasable Programmable Read Only Memory), FLASHMemory, Jump Drive, and the like), magnetic storage medium (e.g., tape,magnetic disk drive, and the like), optical storage medium (e.g.,CD-ROM, DVD-ROM, paper card, paper tape and the like) and other types ofprogram memory.

FIG. 3 is a block diagram of the system architecture for a UAV inaccordance with one embodiment. The dashed line 300 demarks theseparation between the turret payload 302 versus the aircraft orfuselage payload 304. The turret payload 302 includes the camera optics,which are not shown for simplicity. The turret payload 302 also includesthe gimbal mechanism 306, responsible for moving the camera opticsthrough a range of azimuthal and elevational angles. Motion is effectedusing pan and tilt microprocessors and motors 308 and 310 in conjunctionwith angular sensors 312 that provide feedback and control for thesemechanisms. EO (electro-optical) and IR (infrared) detectors 314 providesensed information to a circuit 316, comprised of an FPGA for instance,for serializing the data and for interfacing with the detectors, forexample providing instructions regarding size and orientation of framesto be grabbed, commands for AGC measurement, track or stab(stabilization) offsets, and synchronization signals. Track and staboffsets are parameters which affect the region of the detectors that iscaptured and returned in video, and are commands that can be generatedin video processing on the fuselage. Stabilization is an approach formatching a frame with a previous frame in order to remove unintentionalmovements, with the effect of keeping objects in the video stationary.

The output of circuit 316 is transmitted out of the turret into theaircraft. The turret payload 302 can contain other hardware and circuitcomponents for operating the camera such as for manipulation and controlof frame capture, display orientation, scale, format (bayer,monochrome), image stabilization/tracking, AGC measurement, track orstab offset, and synchronization signals. However, the bulk of the videoimage processing is performed not by circuitry in the turret payload302, as in prior art approaches, but by circuits that are disposed inthe aircraft itself, as part of the aircraft or fuselage payload 304.This reduces the weight of the turret and its size and commensuratedrag, also reducing the amount of heat generated in the turret, whereinlimited heat management measures are available, particularly due to therequirement of water-proofing because of weather exposure. In addition,the size and power (and heat) of the motors required to actuate theturret in the various degrees of freedom are reduced, because the weightand the size of the turret is reduced. The reduction in weight reducesthe inertia of the turret and as such a lighter turret can be turned asfast by smaller motors or faster with the same motors. In addition,costs are reduced by piggy-backing some or all of the video processingonto existing electronics in the aircraft, eliminating redundantcomponents previously found in both the aircraft and the turret.Further, by centralizing the video image processing onto one location inthe aircraft, data from cameras other than those on the turret can bedelivered to the centralized location for processing, reducingredundancy, cost and weight, and possibly drag, even more. Because theUAV is battery operated, these reductions directly impact the airtime(e.g. flight mission time) and performance of the aircraft and arecritical, outcome determinative factors. The centralized approach isdepicted in the block diagram of FIG. 4, which shows a central imageprocessor collecting and processing information from multiple camerasincluding a landing camera and surveillance cameras 1 and 2. Only asingle, central image processor is required for these multiple cameras,compounding the size, weight and cost savings. Another advantage of thisapproach is the standardization of the image processing, enablinginterchangeability of the optics of each of the multiple cameras. Thusthe optical components of the camera in the turret for example can bereadily swapped out for more specialized optical functionality—that is,higher power magnification or zoom functionality, for instance—withoutthe need to replace the image processing circuitry as well, or toreconfigure the processing algorithms and protocols as would benecessary if the image processing circuitry had to be replaced with theoptics. It should be noted that a surveillance and a landing camera maynot be operative at the same time as the tasks associated with each aredifferent and separate. Therefore separate video processingfunctionality at each camera may not be necessary, and can be staggeredover time for the two types of cameras. This is also true of the IR andEO cameras, which are often not operated simultaneously, and their useof processing equipment and also be staggered, so that thy both sharethe same equipment.

Returning to FIG. 3, central video image processor 318 is shownconfigured to receive image data and other information from EO and IRdetectors 314 delivered by way of physical USB connections 320 andcommunication channels 322. The communication channels 322 may beselected from various types of connections, including but not limited totwisted pair conductors, coaxial cables, slip rings, or even wirelessconnections. The type of connection used may be a function of the databandwidth and the amount of compression that is applied beforetransmission. Raw, uncompressed data requires minimal processing and cantherefore help reduce the size of the turret. However, the transmissionof raw data imposes the highest bandwidth requirements, and thetransmission path would be configured accordingly, using coaxial or evenoptical cables for example. The received image data and otherinformation is processed by central video image processor 318, whosefunctions may include, but are not limited to, obtaining raw orpartially conditioned data from the detectors 314, obtaining informationon how to display individual frames, including rotating and scalinginformation, performing stabilization and/or tracking, and performingAGC (automatic gain control) measurements and providing results thereof.Central video image processor 318 is also configured to receivenon-image related information, such as that from autopilotmicroprocessor 324. Some or all of this non-image related information isadditionally provided to gimbal 306, augmented with other informationrelating to aircraft state estimates, body rates, mission information,flight mode information, joystick/control information, DTED (groundelevation data used by the payload to estimate where it should bepointing) information and camera control data. Modules (not shown) ofcentral video image processor 318 that can perform the above and otherfunctionalities can include a de-mosaicing module, video conditioningmodule (for color correction, white balance, saturation, and contrast,for instance), individual frame display information module that providesinformation on rotating, scaling and offset, and template matchingmodule for stabilization and tracking, and video compression.

A surveillance method 500 in accordance with one embodiment is describedwith reference to FIGS. 5 and 6. In this method, at 502, a gimbaledcamera 600 (FIG. 6) mounted in a turret exterior to an aircraft fuselage602 is used to collect image information. The image information is thentransmitted, at 504, to a central image processor 604 disposed in theaircraft fuselage. Optionally, this processed image is then transmittedto a remote base station 606 at 506. A second, landing camera 608 alsotransmits its image information to central image processor 604, and,optionally, to remote base station 606. Although the landing camera isshown on the underside of the fuselage, it could be disposed in otherlocations, for example the top side of the fuselage, for UAVs configuredto land “upside down.”

While embodiments and applications have been shown and described, itwould be apparent to those skilled in the art having the benefit of thisdisclosure that many more modifications than mentioned above arepossible without departing from the inventive concepts disclosed herein.The invention, therefore, is not to be restricted except in the spiritof the appended claims.

1. An unmanned aerial vehicle (UAV) comprising: a fuselage; a gimbal-mounted turret having one or more degrees of freedom relative to the fuselage; a camera disposed in the gimbal-mounted turret for motion therewith in the one or more degrees of freedom; and a central video image processor disposed exteriorly of the gimbal-mounted turret, the central video image processor configured to receive and process image data from the camera.
 2. The UAV of claim 1, wherein the central video image processor includes one or more of the following modules: a de-mosaicing module, a video conditioning module, individual frame display information module, and template matching module.
 3. The UAV of claim 1, further comprising an additional camera mounted to the aircraft and coupled to the central video image processor, the central video image processor configured to receive and process image data from the additional camera.
 4. The UAV of claim 1, wherein the additional camera is a landing camera.
 5. A surveillance method comprising: capturing image information using a gimbaled camera mounted in a turret exterior to an aircraft fuselage; transmitting the captured image information to a central image processor disposed in the aircraft fuselage; and processing the transmitted captured image information in the central image processor.
 6. The method of claim 5, further comprising transmitting information processed by the central image processor to a remote location.
 7. The method of claim 5, further comprising capturing image information using an additional camera mounted exteriorly of the fuselage and transmitting the captured image information from the additional camera to a central image processor disposed in the aircraft fuselage.
 8. A device comprising: means for capturing image information using a gimbaled camera mounted in a turret exterior to an aircraft fuselage; means for transmitting the captured image information to a central image processor disposed in the aircraft fuselage; and means for processing the transmitted captured image information in the central image processor.
 9. The method of claim 8, further comprising means for transmitting information processed by the central image processor to a remote location.
 10. The method of claim 8, further comprising means for capturing image information using an additional camera mounted exteriorly of the fuselage and transmitting the captured image information from the additional camera to a central image processor disposed in the aircraft fuselage. 